1. Field of the Invention
The present invention generally relates to automobile grilles positioned at the automobile's front end. More specifically, this invention relates to an automobile grille which is capable of elastic deformation yet is rigidly directly or indirectly attached to the engine hood, front end automobile body panel, automobile bumper, or a combination thereof. The flexible grille is able to withstand substantial flexure when the automobile bumper sustains an impact by an object. The flexible grille of the present invention is particularly well suited for use with impact-absorbing bumpers which automatically rebound from a frontal impact.
2. Description of the Prior Art
Automobile grilles have generally evolved from what once was primarily a safety barrier to protect an individual from injury as well as to prevent damage to an automobile's radiator to its present status as primarily a decorative feature, though also often serving as the primary source of ventilation to the radiator. Accordingly, the earlier grilles were formed from metal so as to have adequate strength to deflect objects from hitting the radiator. Today, the role of the automobile grille as a barrier has been largely supplanted by modern practices which position the radiator such that it is protected by other means. But for styling purposes, the automobile grille is still present on most modern automobiles, though generally formed from plastic to save weight.
With the advent of energy or impact-absorbing bumpers, automobile grilles have been required to undergo significant design changes in order to accommodate the stroke of the bumper, which commonly can be as much as 3 to 4 inches. Current grille designs have primarily taught three solutions to this problem. The first and traditional solution is to position the grille entirely out of the path of the bumper during recoil after impact. This approach generally entails placing the automobile grille rearward of the bumper, resulting in an extremely square-looking profile which has little appeal according to modern design trends. In addition, such a design is not aerodynamic, and as such this approach is not generally followed, particularly as fuel efficiency becomes increasingly important. A second solution is to completely eliminate the grille, which generally entails sweeping the engine hood down such that it is suspended just above the bumper line. However, this approach has not been widely adopted in that it has rather limited styling appeal. A third solution is to require the grille to be displaceable such that it can pivot or otherwise move out of the bumper's path during energy-absorbing impact. Preferably, this approach allows the grille to be mounted flush with the surrounding hood, front end, body panels and bumper so as to enhance the styling and aerodynamics of the automobile. Such an approach is illustrated by U.S. Pat. No. 3,792,889 to Fuener et al. There, a sequentially moving grille is taught in which the lower edge of the grille is pivotally secured to the automobile body while the upper edge of the grille is allowed to rotate about the lower edge. The upper edge is biased by a spring element in cooperation with a guide rod such that the upper edge is normally flush with the adjacent body panel of the automobile. During impact the rearward travel of the bumper forces the grille to pivot rearwardly about the lower edge and against the spring element.
Another example of the third solution is taught by U.S. Pat. No. 4,753,468 to Szymczak et al, which provides a pivot arm which pivots the grille rearwardly and upwardly during impact. Yet another example is shown in U.S. Pat. No. 4,834,436 to Nguyen, which substantially eliminates the arcuate displacement of the grilles of both Fuener et al and Szymczak et al by employing a four-bar linkage that displaces the grille in an entirely rearward manner during impact. U.S. Pat. No. 4,944,540 to Mansoor et al also seeks to avoid an arcuate path by the grille during impact by a pin and slot arrangement having a return spring.
As can be readily appreciated by those skilled in the art, the above examples corresponding to the third solution all entail additional hardware and space considerations to accommodate the displacement of the grille. In addition, the added hardware is also necessary to adequately support the grille so as to be able to withstand wind resistance and road vibration while the vehicle is in use. But the additional hardware requirement itself is a disadvantage when it comes to both costs and weight from the standpoint of the vehicle manufacturer. The added costs entailed in purchasing and installing the above necessary hardware to achieve the desired results will generally be substantial, while the additional weight penalty adversely affects the performance and fuel economy of the vehicle. Both considerations are of primary importance with the present highly competitive automobile market.
An approach which tends to avoid the problems noted above is illustrated in U.S. Pat. No. 2,578,068 to Johnson. Johnson teaches a resilient grille and bumper combination which is resiliently attached at its lower edge to the automobile's frame. Johnson further teaches that the combined grille and bumper combination is capable of only a small predetermined amount of flexing or pivotal movement upon engagement with an object. A more modern version of this approach is illustrated by U.S. Pat. No. 4,917,203 to Sacco et al. There, a grille is disclosed which is supported within a radiator cover. The radiator cover is secured to and suspended from the engine hood by resilient inner plates which allow the radiator cover to pivot elastically about the edge of the hood when the bumper is impacted. An advantage to the above structure is that the added hardware and weight noted with the teachings of Fuener et al, Szymczak et al, Nguyen, and Mansoor et al is avoided. In addition, Sacco et al particularly illustrate the styling and aerodynamic benefits to the automobile when the grille is mounted flush with the surrounding body panels and bumper.
However, the grilles taugh by both Johnson and Sacco et al have two significant disadvantages. First, the space requirements for the arcuate motion, recognized as being undesirably by Nguyen, are again present. As can be seen with the radiator cover of Sacco et al, the arcuate motion of the entire radiator cover assembly requires a large arcuate path and a suitable stop to allow the radiator cover to deflect during impact. Consequently, a significant amount of space must be provided for the radiator cover to be displaced within the front end of the automobile. Secondly, the radiator cover can only be attached along one edge so as to allow the resilient pivot action between the radiator cover and the hood. The Sacco et al radiator cover is entirely suspended from the engine hood in a cantilever arrangement. As a consequence, the radiator cover is highly susceptible to wind and road vibrations, clearly an undesirable characteristic.
An obvious solution to this problem would be to make the inner plates taught by Sacco et al stiffer. But to do so would largely defeat the requirement that the radiator cover assembly be sufficiently resilient to deflect during impact. A second alternative solution to this problem would be to secure the lower edge of the radiator cover to the body of the automobile. However, to do so would prevent the radiator cover from deflecting as intended, thus reducing its capability to resiliently deflect with the bumper during impact.
From the above discussion, it can be readily appreciated that the prior art does not disclose an automobile grille which has both the advantages of being able to move with the bumper during impact and being sufficiently supported by the automobile body, while simultaneously avoiding the need for added hardware and weight for purposes of providing the movement and support features. Nor does the prior art teach or suggest an attempt to modify the structure of an automobile grille itself to provide a predetermined resiliency which would enable the grille to deflect with the bumper and absorb an impact with the bumper while still remaining securely attached to the automobile body.
Accordingly, what is needed is a cost-efficient automobile grille capable of being mounted substantially flush to the surrounding automobile front end body panels and/or bumper which can be rigidly attached to the automobile body front end panels to withstand wind and road vibration without the need for additional hardware, while also being provided with a predetermined degree of elasticity in critical areas of the grille such that the yield strength of the grille's material will not be exceeded during impact and displacement of the bumper and allow the grille to return to its initial position without any adverse effects as a result of the impact and/or movement.